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Chemical Woodburning 


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Chemical Woodburning 

Written By: Sean Michael Ragan 


Felt (1 sheet) 

Heat gun (1) 

Measuring cup (1) 

Measuring spoon (1) 

Spray bottled) 

Stamp (1) 

Mine was cobbled together from foam 
rubber letters, a scrap of MDF, and a 
strip of carpet tape. 

Tray (1) 
aluminum or plastic 

Weighing paper (1 sheet) 

Just about any piece of smooth paper 

will do. 


Ammonium chloride (100g) 
Commonly called "sal ammoniac. " Get 
the powdered form if you can; solid 
bricks sold for tinning soldering irons 
can be broken up in a mortar and pestle. 

Water (2 cups) 

/ used carbon filtered tap water from my 

kitchen sink. 

Wooden workpiece (1) 
to be burned. 


If you want to apply a maker's mark or other repeated pyrograph to wooden goods, but can't 
justify the expense of a custom branding iron, an indistinguishable effect can be achieved by 
applying a strong solution of ammonium chloride, for instance using a foam rubber stamp, 

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Chemical Woodburning 

followed by relatively mild heat, 

On heating, ammonium chloride decomposes into ammonia gas and strong hydrochloric 
acid. Ammonia diffuses away into the atmosphere, leaving the strong acid behind, which 
burns the wood. The resulting chemical burn is identical to a heat burn in most respects. 

This process sounds nastier than it is, in practice, and although prudence dictates erring on 
the side of caution and working with plenty of ventilation, the process does not produce a 
noticeable smell either of ammonia or of HCI. The only detectable odor is burning wood. 

• For my simple "MAKE" stamp, I used these plastic-backed 1.5" foam-rubber letters from a 
hobby store. 

• Apply a strip of carpet tape to a suitably-sized piece of MDF, plywood, or other flat back. 
Remove the tape backing. 

• Arrange the letters as needed and push down the backing around each to fix it in place. 

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Chemical Woodburning 

• Although the photo shows me working with bare hands, you should err on the side 
of caution and wear latex or nitrile gloves, as well as goggles, from this point 
onward in the project. 

• Take a piece of paper and fold it in half lengthwise. 

• Lay it out on your work surface, then measure 5 level tablespoons of ammonium chloride 
onto the fold. 

• Gather up the paper from the long edges and form a channel, pouring as shown, using the 
fold to direct the solid into the mouth of the bottle. 

• If you want more or less than 500 mL of "ink," the formula is 1 tablespoon 
ammonium chloride per 100 mL water. 

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Chemical Woodburning 

Pour 500 mL of warm water into the bottle on top of the solid ammonium chloride. Tap 
water should be fine. 

Put the sprayer, or a matching cap, on the bottle and tighten it down securely. 

Shake the bottle gently until all the ammonium chloride is dissolved. 

• Set out a flat, shallow, aluminum or plastic tray that's big enough to accept your stamp. 

• Line the tray with felt. 

• Saturate the felt by misting it generously with ammonium chloride "ink" from the spray 

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Chemical Woodburning 

• You'll want to practice this process a couple times on scrap wood before trying it on m^ 
anything important. 1*1 

• Put the stamp onto the felt and press down with some force to "ink" it. 

• Transfer the stamp to the workpiece, line it up carefully, and press down with about the 
same force to transfer the ink. 

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Chemical Woodburning 



If you let the "ink" sit on a wooden surface too long, it may diffuse along the grain 
and blur the image. 


Immediately after applying the stamp, pick up the heat gun and begin applying heat. I used 
the "high" setting on my heat gun. 

Play the heat gun evenly across the surface of the work. Within a minute or two the inked 
areas will begin to turn yellow, then brown, then brownish-black. 

You're done! For all practical purposes, the resulting chemical burn is indistinguishable 
from a heat burn. It is waterproof and can be finished or otherwise treated like a 
conventional pyrograph. 

The "ink" described here is nothing more than an 80% saturated solution of ammonium chloride. 
Though it works well enough as described, there's plenty of room for improvement of its handling 
qualities. Adding egg whites or other thickener, for instance, might improve the handling qualities 
and/or reduce the tendency of the ink to diffuse along grain lines. 

There is, moreover, no reason this material has to be applied with a stamp. It might also be 
applied with a stencil, a marker, a brush, a printer, or some other means, and each of these 
might have interesting applications and/or merit adjustments to the properties of the ink itself. 

Other substrates might also be tested. Leather, perhaps? 

This document was last generated on 201 2-1 0-31 1 0:29:1 2 AM. 

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